A method to measure time constant of broadband low resistance shunt

Summary

The measurement of impulse and high-frequency high current is usually carried out. The measuring methods widely used include broadband current monitor method. No-inductance coaxial resistor shunt could not only be used in the measurement of transient high current, but also be used as standard instrument in the metrology of broadband current monitors. The precondition of the calibration of broadband current monitors with resistor shunt is to obtain the bandwidth or the time constant of the reference shunt. The commonly used method is to excite the shunt with a square wave current source, and measure the rise time of the output of the shunt. Then the frequency response can be calculated equivalently. In this paper, it was deduced that the influence induced by of the difference between RAC (AC resistance of the shunt) and RDC (DC resistance of the shunt) to the uncertainty of the calibration is only 0.08% when the frequency was 10 MHz. And when the resistance of the shunt was smaller than 1 O, the time constant would be decided by the residual inductance of the shunt. A calibration method of the time constant of the non-inductive low resistance shunt was put forward. The verification measurement was also carried out. The measurement verified that the measurement method was practical and convenient in measuring the constant and the bandwidth of a low resistance shunt.

Additional informations

Authors

Y. PAN, H. SHAO

Keywords

shunt, broadband, calibration, current monitor